| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a control system for an internal combustion engine by which at the time of return from a fuel cut (FC), occurrence of misfire is controlled by positively raising the threshold for misfire with reference to the concentration of residual burned-gas in the combustion chamber. Ž<P>SOLUTION: The opening degree of an EGR-valve and timing for valve-opening of an intake-valve are controlled respectively, usually, according to operation conditions of the internal combustion engine, to a normal opening and to a normal timing. Whereas, in the course of FC, or within a specific period after return from FC, opening degree of the EGR-valve is maintained at zero; while, when the timing for opening the intake valve is controlled in the intake stroke toward the retard side farther than in the normal timing, and toward the retard side farther than the exhaust valve-closing timing (control for intake-valve retard-opening). Thus, pressure difference between the front and the rear of the intake-valve directly after opening of the intake valve is increased, and the intake air flow immediately after the opening of the intake-valve is increased. As a result, atomization of fuel spray to be mixed with intake air is accelerated to raise the misfire limit for the residual burned-gas concentration, and occurrence of misfire at FC return, where misfire is easy to occur, is suppressed. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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